DE3932469A1 - ANTIMICROBIAL HYDROXYAPATITE POWDER AND METHOD FOR THE PRODUCTION THEREOF - Google Patents

Description

The invention relates to antimicrobial agents in which a metal ion with antimicrobial property, such as silver, copper and zinc ions, or an organic antimicrobial agent, the one or more of hinokitiol, tannin, lysozyme, protamine and Sorbic acid selected in hydroxyapatite powders that has a good affinity to living body tissue have and on a large scale on medical, dental and hygienic areas can be used, such as artificial Bones, artificial roots, dentifrices, dental cement, Supplementary material for bone loss and cosmetic Materials. The invention also relates to methods of preparation this means.

The antimicrobial agents are widely used in the fields medicines, medical instruments, cosmetics, food, Kitchen utensils, packaging materials, filters, clothing and various other goods. Especially  are the antimicrobial and preservative agents in places useful where many people come together to eat, drink, to inhale or come into contact with each other.

The antimicrobial agents are divided into two groups, namely the synthetic or natural inorganic Group and the synthetic or natural organic group. The antimicrobials now used in practice are organic substances; the inorganic antimicrobial agents are not yet used because of the antimicrobial effects said metals and their salts of said metal ions depend, and these ions can only in the aqueous solutions be used and have a strong toxicity and disadvantages, like coloring and color changes. The organic antimicrobial However, funds also have disadvantages, such as high volatility, low heat resistance, color and good solubility in water and organic solvents. Therefore, their applications are limited. Accordingly, various proposals have been made made to the disadvantages of organic antimicrobials to eliminate. For example, combinations of hinokitiol with alum and calcium salt suggested to staining the hinokitiol prevent (Japanese Patent Laid-Open Sho 59-2 24 677), or the salt or its inclusion compound is used (Japanese Patent Laid-Open Sho 61-1 08359). In general become those to be used in a living organism Materials made germ-free by heating or ethylene oxide and kept in a germ-free state, to ensure the reproduction and adhesion prevent unwanted bacteria. Disinfection by But ethylene oxides has the disadvantages that ethylene oxides in the materials be retained and contaminate the materials, when these materials are used. Also, these materials are often used in parts of disease centers, and therefore there is a possibility of bacteria being raised in the herds become. The composition of the hydroxyapatite is substantially the same as the composition of living bone tissue. It therefore has good affinity for living body tissue  and as excellent features as the body materials. Proteins, amino acids and other organic substances however, readily absorbed in hydroxyapatite, and it is found in the Hydroxyapatite then also easily absorbed and grown bacteria. When hydroxyapatite as a material of the living organism is used, it is therefore necessary to remove the pollution of hydroxyapatite with bacteria. To the problem to solve the contamination of hydroxyapatite, it is in Consider, along with the hydroxyapatite antimicrobial To use funds. However, since the commonly used antimicrobial Medium organic substances with low heat resistance and good solubility, is the heat treatment this means difficult. Therefore, the commonly used antimicrobial agent difficult as materials for the living organism and for medical instruments use.

Even if the organic antimicrobials are high Give security, the use of these funds must be limited, because unfavorable problems, such as changes in taste, odor changes and discoloration can occur when they are food be added directly.

When using these agents as a soaking substance in the way be that the means the substrate, such as paper, textile fabric and water-receptive polymer or absorbed by the substrate reduces sublimation the agent from the surface of the impregnated substance during the drying process the antimicrobial effects. Also in the practical use of the impregnated substances The antimicrobial agents are removed from the surface of the Substances volatilize, dissolve and remove, and then they can unwanted adverse damage occur. From the point of view The durability and safety therefore include the use and preserving the impregnated substances difficult Problems. When the organic antimicrobial agent films and compact resins can be added directly, the antimicrobial  Forces through evolving decomposition and sublimation lost to the antimicrobial agent. It's tough, the said agents without loss of antimicrobial activity to process.

Methods were tested in which inorganic and organic antimicrobial agents are absorbed on zeolite and in easy to handle. However, the problems occurred that zeolite only comparatively small amounts of the antimicrobial Absorbed by means. When ceramic, such as SiO, CaCO₃ and Ca₃ (PO₄) ₃, is used in place of zeolite, is the restraint the antimicrobial agent in the ceramic very low. When the antimicrobial agent-containing ceramic products, such as cosmetics, resins, fibers, paper and filters in order to give it an antimicrobial property, large quantities of the ceramic material must be used, to achieve the antimicrobial effect. The quality of the products decreases however, if these large quantities of the mentioned ceramic material.

The object of the invention is to provide antimicrobial Agents in the form of powders with good affinity for living body tissue and strong antimicrobial properties without a loss of antimicrobial effect through sublimation, evaporation, Solution and deposition of antimicrobial agents entry. In addition, antimicrobial powder agents are to be created be the consistency, security and consistent Have quality and by mixing with other substances be used without the contamination with undesirable Bacteria is to be considered. Furthermore, according to the present Invention a process for the preparation of these agents be created.

As discussed above, hydroxyapatites have good affinity to the living body and different applications. On However, hydroxyapatites easily plant unwanted bacteria continued. According to the invention, hydroxyapatites may be used as materials  of the living body by using the hydroxyapatite gives antimicrobial properties, and the conventional Hydroxyapatites, which easily produce unwanted bacteria, are changed to new hydroxyapatites, which is a good Have affinity to the living organism, do not produce bacteria and easy to handle. There are also hinokitiol, Tannin, lysozyme, protamine and sorbic acid as common antimicrobial Means used. Hinokitiol, however, has a considerable Vaporizability, and hinokitiol and tannin are likely oxidized in the atmosphere. The antimicrobial powers and the color of hinokitiol and tannin are in the presence of Metals, and then specific methods are needed to maintain these antimicrobial effects over long periods of time.

Lysozyme is a basic enzyme that is difficult to handle is. Protamine is water soluble, and its uses are limited. Sorbic acid is oxidized in the atmosphere and coloured. When their solution is heated, one unexpectedly sets found that sorbic acid evaporates together with the water vapor. However, it was known that these antimicrobial agents on hydroxyapatites are specifically absorbed and these to hydroxyapatites absorbed means do not go into solution and into the Solution when the hydroxyapatites are handled. The absorbed antimicrobial agents are against a Heat treatment resistant and do not change their property, so that the antimicrobial effects are maintained for a long period of time stay.

The invention is the creation of antimicrobial Hydroxyapatites in which the antimicrobial metal ions and one or more antimicrobial agents are absorbed under Hinokitiol, tannin, lysozyme, protamine and sorbic acid and methods of making these hydroxyapatites. In certain cases, calcium ions are in the hydroxyapatites substituted by antimicrobial metals and their metal ions,  or said metal ions are in the holes of the apatite crystals occurred. Coexistence with antimicrobial metal phosphates is possible. The antimicrobial metals and their ions have the meaning of silver, copper and zinc metal and their ions.

The antimicrobial hydroxyapatites, the antimicrobial Metals and their ions are stable and heat resistant. It is possible to use the antimicrobial hydroxyapatites with materials of the living body because they are in powder form.

The hydroxyapatites used in the present invention are the synthetic and natural hydroxyapatites, as indicated by the formula Ca₁₀ (PO₄) ₆ (OH) ₂; further may be apatites in which part of the OH residues of the hydroxyapatite is replaced by F⁻ or Br⁻, also as hydroxyapatites be used.

The antimicrobial hydroxyapatites, which are the antimicrobial Metals and metal ions can be prepared as follows become:

• (i) When hydroxyapatites are produced, the antimicrobial Metal salts in addition to the Hydroxyapatiten ago.
• (ii) Hydroxyapatites are treated with the antimicrobial metal salts implemented.

That is, calcium chloride solutions are dropped into solutions, the disodium monohydrogen phosphates and those under silver, Copper and zinc salts selected antimicrobial metal salts contain. Hydroxyapatite is replaced by a common Process produced. The produced hydroxyapatites are filtered, washed with distilled water, dried and crushed. Or the hydroxyapatites containing conventional methods are suspended in water, and the water-soluble antimicrobial metal salts are added to the suspension. Then the precipitates are washed with distilled water, dried and crushed. The acid radicals, metal salts and calcium salts,  by replacing the calcium ion of the hydroxyapatite were formed against the metal ions, lying next to the antimicrobial hydroxyapatites. Then it is necessary the equilibrium contaminants present through intensive washing of the antimicrobial hydroxyapatites with water to remove.

The amounts of antimicrobial contained in the hydroxyapatites Metal ions are optionally chosen by the type of antimicrobial metal salts, the concentration of the treatment solution and the reaction temperature is set. In some Cases is the structure of the manufactured antimicrobial However, hydroxyapatite altered from the apatite structure; then the amounts of metal salts per hydroxyapatite are preferably to 30% or less, preferably to 5 to 0.0001% limited. The antimicrobial obtained by the above-mentioned methods Hydroxyapatites have antimicrobial effects over a long period of time, and the amounts of metal dissolved in water are a few ppm or less. These products can then safely used, and the antimicrobial effects arise by adding 10% or less, preferably 0.5 to 5% hydroxyapatite to the other materials.

Meanwhile, the methods of introducing at least one substance selected from hinokitiol, tannin, lysozyme, protamine and sorbic acid into hydroxyapatites are described as follows:
The antimicrobials are dissolved in water and their solutions are added to hydroxyapatite powders. Then the powders are washed extensively with water, solvent and the mixture thereof so that the antimicrobials not fixed on the hydroxyapatites are completely washed out. The antimicrobial hydroxyapatites are dried and comminuted. When the hydroxyapatites are formed by a common wetting method, the antimicrobial agents and the hydroxyapatite materials coexist.

The amounts of antimicrobial agents to be applied to the hydroxyapatites Means may be selected according to the type of antimicrobial Agent, solution concentration and method of application the hydroxyapatites are selected. The on the hydroxyapatites However, applied amounts of antimicrobial agents are limited to 0.01 to 10% based on hydroxyapatite.

The antimicrobial hydroxyapatites obtained by these methods retain the antimicrobial effects over one long period of time, and those superimposed on the hydroxyapatite antimicrobials are not dissolved in water and alcohol. The hydroxyapatites are characterized by a safe use out, and develop their antimicrobial effects when taking the hydroxyapatites in the other materials an amount of 50% or less, preferably 0.1 to 20% added.

The antimicrobial hydroxyapatites of the invention are used because they have high security and good affinity for living body in the fields of foods, materials of the living body, cosmetics, fibers, cellulose, Plastics, filters and water absorption polymers have, at which the antimicrobial effects are required. at Use in a dentifrice is additionally an anticaries effect through the action of protein removal and through achieved the fine filling effect of hydroxyapatite. The pharmaceutical Remedies remain with hydroxyapatite for a long time on the tooth surface, and to a large extent the dental caries preventive agents may develop according to the invention. The The present invention will now be described in detail with reference to FIG to a number of examples.

example 1

8 g of copper sulfate, 1.2 l of a 0.1 M solution of Na₂HPO₄ added and dissolved. 1 l of a 0.1 M CaCl₂ solution is called Solution added dropwise with stirring. The hydroxyapatites are produced by a common method. The Products are washed thoroughly with distilled water, dried  and crushed. Antimicrobial, copper is obtained containing hydroxyapatite powder.

Example 2

The same procedure as in Example 1 is carried out with the difference that instead of copper sulphate 6 g Zinc sulfate can be used. You get antimicrobial, zinc containing hydroxyapatite powder.

Example 3

The same procedure as in Example 1 is carried out with the difference that instead of 8 g of copper sulfate about 1 g of copper sulfate and about 2 g of zinc sulfate can be used. Antimicrobial, zinc and copper-containing hydroxyapatite powders are obtained.

Example 4

While stirring, about 2 g of silver nitrate are distilled in 1 liter Water is dissolved, and the pH is adjusted by adding Ammonia water from neutral to alkaline. It will 1000 ml of a 0.1 M CaCl₂ solution and 600 ml of a 0.1 M Na₂HPO₄ solution added dropwise. The hydroxyapatites are after the usual method by adjusting the pH of neutral prepared alkaline with ammonia water. The products obtained are sufficiently washed with distilled water, dried and crushed. You get antimicrobial, silver containing hydroxyapatite powder.

Example 5

The same procedure is carried out as in Example 4 with the difference that instead of 2 g silver nitrate 0.1 g of silver nitrate, 0.2 g of copper sulfate and 0.4 g of zinc sulfate used become. One receives antimicrobial, silver, copper and Zinc-containing hydroxyapatite powder.

Example 6

1 g of silver nitrate and 0.8 g of copper sulfate become 100 ml of a 1 M calcium hydroxide solution is added and then 0.2 M Added phosphate solution with stirring. The hydroxyapatites are produced by the usual method. The products will be  completely washed with distilled water, dried and crushed. You get antimicrobial, silver and copper containing hydroxyapatite powder.

Example 7

The same procedure is carried out as in Example 6, wherein instead of 1 g of silver nitrate and 0.8 g of copper sulfate 2 g of zinc sulfate and 0.4 g of sodium fluoride are used. Antimicrobial, zinc and fluoride containing Hydroxyapatite powder.

Example 8

10 g of hydroxyapatite, 0.5 g of silver nitrate and 1.3 g of zinc sulfate are added with stirring 100 ml of distilled water. The Products are completely washed with distilled water, dried and crushed. You get antimicrobial, silver and copper-containing hydroxyapatite powders.

Example 9

The same procedure is carried out as in Example 8 with the difference that instead of 0.5 g of silver nitrate 0.8 g of copper sulfate is used. You get antimicrobial, Zinc and copper-containing hydroxyapatite powders.

Example 10 Tests for dissolving the metals

1 g of the antimicrobial prepared in the above examples Hydroxyapatite powder is distilled with stirring 100 ml Water added; then the dissolved metal quantities become measured. The results show that the dissolved metal amounts are less than 100 ppb.

Example 11 Tests of antimicrobial activity

There are mixtures samples by adding the in the examples 1 to 9 obtained antimicrobial hydroxyapatite powder in one Amount of 1% to hydroxyapatite. The antimicrobial Results of these mixtures are as follows:

Example 12 Tests for antimicrobial activity

The products obtained in Example 8 become 100 ml of a Cloudy, made up of 100 g of hydroxyapatite and 200 ml of distilled water exists in the amount of 0.001%, 0.005%, 0.01% and 0.1%, respectively added.

The results show that additives of 0.005% or more are successful.

Example 13 Tests for antimicrobial activity

The products obtained in Example 5 become binders added and the materials are compacted for molding. The molded products are sintered at 500 ° C; you get Pellets with 3 cm diameter. These pellets are made of pure antimicrobial Hydroxyapatite produced. The antimicrobial Activity testing is done using these pellets.

You get the following results:

From the results of Examples 11 to 13 it is clear that the antimicrobial hydroxyapatite powder from the concentration 100% to a concentration of 0.005% in the mixture can be used with other materials.

Example 14

1.0 kg of hydroxyapatite and 0.0016 g of silver nitrate become 10 l distilled water is added and it is heated for 1 hour touched. The products are completely distilled Washed water, dried and crushed.

Antimicrobial, 0.001% silver containing Hydroxyapatite powder. The silver solution test is using this Product carried out; It is found that silver is not goes into solution. The antimicrobial activity test is under Use of a mixture of 1% of said product and 99% hydroxyapatite. Hydroxyapatite serves as Control material.

The results are as follows:

Example 15

1.5 g of hinokitiol are dissolved in ethanol. 100 g of hydroxyapatite added with stirring of the solution. The products become intense washed with ethanol and distilled water, dried and crushed. This gives antimicrobial, 1.5% Hinokitiol containing hydroxyapatite powder.  

Example 16

1.0 g of hinokitiol and 0.4 g of tannin are dissolved in ethanol, and hydroxyapatite is added while stirring the solution. The Products are completely made with ethanol and distilled water washed, then dried and crushed. You get antimicrobial, 1.0% hinokitiol and 0.4% tannin-containing hydroxyapatite powder.

Example 17

5 g of lysozyme are dissolved in distilled water, and 100 g of hydroxyapatite are added while stirring the solution. The products become intense with ethanol and distilled water washed, then dried and crushed. You get antimicrobial, 5% lysozyme-containing hydroxyapatite powder.

Example 18

2.0 g of protamine are dissolved in 500 ml of distilled water, and hydroxyapatites are added while stirring the solution. The products become intense with distilled water washed, dried and crushed. You get antimicrobial, 2% protamine-containing hydroxyapatite powder.

Example 19

2.0 g of sorbic acid are dissolved in 500 ml of ethanol water, and 100 g hydroxyapatites are added with stirring. The products Be intense with ethanol and distilled water washed, dried and crushed. Antimicrobial, containing 2% sorbic acid Hydroxyapatite powder.

Example 20

50 ml of a 10% Hinokitiol solution will be 1 l one 1 M Ca (OH) ₂ solution is added, and it is stirred with 0.2 M Add phosphate solution. Then be following the usual method Hydroxyapatites produced. The products are intensively with Ethanol and distilled water, dried and crushed. Antimicrobial containing 5% hinokitiol is obtained Hydroxyapatite powder.  

Example 21

10 g of the antimicrobial prepared according to the above examples Hydroxyapatite powder is distilled in 100 ml Suspended water and stirred. The dissolved amounts of contained antimicrobial agent are measured. The results show that these remedies are not solved in any case become.

Example 22

Antimicrobial activity tests will be conducted with the in Examples 15 to 19 products obtained.

Example 23

The products obtained in Example 20 become 100 g Containing hydroxyapatite and 200 ml of distilled water Cloudy added in the amounts of 0.2% and 1.0%. It will antimicrobial tests on E. coli.

The antimicrobial and antibacteriostatic effect of antimicrobial hydroxyapatite powder is from the antimicrobial Tests of Examples 22 and 23 can be seen.  

Reference Example 1

Ceramic powder (hydroxyapatite, CaHPO₄, CaH₄ (PO₄) ₃, Ca₃ (PO₄) ₂, calcium pyrophosphate and zeolite) are hinokitiol solutions added to different concentrations, and the Hinokitiol is absorbed by the ceramic powders with stirring. The ceramic is then intensively mixed with ethanol and distilled Washed water and not absorbed by the ceramic Hinokitiol is washed out of the ceramic. Then be measured Hinokitiolmengen absorbed by the ceramic.

The results in Table I are absorbed maximum levels specified.

sample maximum absorbed amounts hydroxyapatite 3.20 CaHPO₄ 0.04 CaH₄ (PO₄) ₂ 0.03 Ca₃ (PO₄) ₂ 0.14 calcium pyrophosphate 0.09 zeolite 0.05

Reference Example 2

There are the hydroxyapatite, Ca₃ (PO₄) ₂ and zeolite maximum absorbed amounts of various organic antimicrobial Measured means.

The results are given in Table II:

Table II

From reference examples 1 and 2 it is clear that hinokitiol, Tannin, lysozyme, protamine and sorbic acid of hydroxyapatite in remarkable compared to the other ceramics Quantities is absorbed.

Claims (6)

1. antimicrobial hydroxyapatite powders, characterized in that they contain at least one antimicrobial metal ion, which is selected from silver, copper and zinc ions. 2. antimicrobial hydroxyapatite powder according to claim 1, characterized characterized in that in the hydroxyapatite 0.0001 to 5 wt .-% contain antimicrobial metal ions. 3. Process for the preparation of antimicrobial hydroxyapatite powders, characterized in that solutions, the disodium monohydrogenphosphate and at least one among silver, copper and zinc salts containing selected antimicrobial metal salt, calcium chloride solutions Add and collect the rainfall. 4. antimicrobial hydroxyapatite powder, characterized that one or more of hinokitiol, tannin, lysozyme, protamine, and sorbic acid contain selected antimicrobial agents.   5. antimicrobial hydroxyapatite powder according to claim 4, characterized in that the hydroxyapatite is 0.01 to 10% by weight Contains antimicrobial agent. 6. Process for the preparation of antimicrobial hydroxyapatite powders characterized in that on the hydroxyapatite a or more among hinokitiol, tannin, lysozyme, protamine and Sorbic acid selected antimicrobial agents are absorbed.